The conventional switch case generally includes a cap and a seat that are coupled through tenons and mortises as shown in FIG. 1 to form a housing chamber inside to hold switch elements. Such a structure has drawbacks, notably: 1. The tenons and mortises have tolerances which make coupling of the cap and seat not precise and firm, and loose coupling occurs; 2. As the cap and seat have tolerances on the coupling surface, moisture tends to enter the switch and results in damage of the conductive elements in the switch; 3. Expensive molds have to be made to produce the mating tenons and mortises, hence the cost is higher.
FIG. 2 illustrates another conventional switch. It has a cap and a seat fastened through a bonding material on the coupling surface. Such a structure can prevent the moisture from entering the switch so that the conductive elements are less likely to be damaged. The production cost also is lower. However, to evenly dispense the bonding material on the bonding surface is difficult, and the bonding material easily overflows from the flat bonding surface under pressure during fastening process to smear the interior or exterior of the switch. The switch elements could be tampered and malfunction or result in poor contact. The production yield could suffer and the production cost could increase.
R.O.C. patent publication No. 484748 discloses a waterproof switch which includes a hollow base with an open end and a pushbutton located on the open end. The inner wall of the base at the open end has at least one jutting detent wall, and the inner walls of the detent wall and the base are interposed by a trough. The trough has at least one channeling port directing outwards to discharge unwanted liquid and external material. It is waterproof and can prevent liquid and external material from entering the switch. But the air contains moisture which still can seep into the switch. Hence how to develop a switch with a case which can be coupled firmly to fend off moisture and reduce damage of the conductive elements in the switch is an issue remained to be resolved in the industry.
Other references of switch with the seat and cap coupled through latches can be found in R.O.C. patent publication Nos. 531036, 515561 and 458358.